Brake mechanism



March 6, 1928. H. PIEPER BRAKE MEoHANIsu Filed April 15. 1926 asheets-Sneet 1 nnnnnnL 'e EEZ . Hen/rl' ZE/957' March 6, 1928. 1,661,621

H. PIEPER BRAKE MBCHANISM Filed April 15. 1926 5 Sheets-Sheet?.

Henri-Ie e7# March 6, 1928. l

H. P11-:PER

BRAKE MECHANISM 5 Sheets-Sheet 3 Filed April l5. 1926 wvwfaf". Henn-".212 eff- Patented Mar. 6, 1928.

UNITED STATES Parleur OFFICE.

HENRI PIEPER, F BRUSSELS, BELGIUM, ASSIGNOR TO COMPAGNIE INTERNATIONALE DES FREINS AUTOMATIQUES, SOCIETE ANONYME, OF LIEGE, BELGIUM.

BRAKE MECHANISM.

Application filed April 15, 1926, Serial No. 102,180, and in Belgium September 10, 1925.

The invention relates to a brake installation in which an intermediate liquid is employed in order to withstand the reaction the brake mechanism undergoes when the slices are pressed against the wheels; this reaction, which is communicated to the liquid by a piston connected to the brake mechanism, being transmit-ted either to the frame or to a piston upon which the braking force l0 is exerted. y

In order to regulate automatically the distance which exists in the releasing posi-V tion between the shoes and the wheel, the invention provides means whereby the shoes are applied against the wheels after a predetermined movement of the-working member; the supplementary movement being utilized for obtaining the braking action.

These means may be such that as soon as the braking operation has commenced, liquid is introduced into the space in which the piston connected to the brake mechanism moves 'in order that the shoes may be immediately pressed against the Wheels, after which, this liquid being capable of displacement in certain chiots, the above predetermined movement oi' the working member is produced without exerting a braking `act-ion, this last being only commenced when the said ducts are closed after the predetermined stroke or movement has been effected.

These ducts are closed durin the Whole of the releasing stroke so that t e space between the shoes and the wheels obtained at the above predetermined movement.

Each ot the figures shown 1n the accompanying drawings represents, by way ot' eX-,

Fig. 4 shows another modicatioirin which the several valves, for the most part, are controlled electrically.

In the construction shown in Figure 1 the space 6 comprised between the pistons 18 and 57 may be connected by a duct 11 with a resrelease of the brakes always corresponds tov .ervoir 9 containing liquid under pressure; 1n this duct 11 is placed a valve l2 normally applied upon` its seating by aV spring the stem ofwhich valve is tixed to the core 63 of a solenoid. This Solenoid is interposed in an electric circuit 64 which may be broken at two points, that is to say by the displacement of the handle 65 of a cont-roller which must occupy the position indicated in dotted lines in order to close the circuit and at another pointby the displacement of the pin 66 carried by the piston 18 until it is no longer in engagement with the fixed contact 67, the result of which is to break the circuit.

The handle. 65 of the controller is connected to operate a valve l2 included in a duct or passage leading from reservoir 9` to a point back of piston 18, so that when it occupies the position shown in dotted lines, not only is the electric circuit 64 closed but said valve 12 is opened and iiuid under-pressure acting to move piston 18' to the right may be admitted behind the piston at the same time or a little later.

It also results that as soon as the handle 65 is brought into the position shown in dotted lines, the valve 12` rises by the actionoil the solenoid, admit-ting to the space 6 comprised between the pistons 18 and 57 liquid under pressure which forces immediately the piston 57 toward-s the right, thus rocking the brake lever 1 in the same direct-ion and applying the shoe 3 againstthe wheel el; at the same time the piston 18 continues its movement to the right and the liquid ahead of it in the space 6 is thus forced back into the reservoir 9, this back flow continuing until the valve l2 is closed4 which takes place when the contact is broken bet-Ween the members 66 and 67 afterk apredetermined stroke of the piston 18. This stroke will be equal to the distance Z and will have no effect on the braking proper; this last being effected afterwards by a new displacement of the piston 18 to the right.

The releasing of the brakes is obtained by putting the handle 65 in the position shown in full lines so that the piston V18 may bey brought back into the initial position shown inthe ligure by the action of an appropriate means .not shown, the piston 57 coming back, automatically under the action of the return spring 7 of the braking mechanism.

During this return movement of piston 18 msY the circuit 671 will not close notwithstanding the reengagement of contacts 66 and 67, because it will be broken by displacement of the handle (55 of the controller; the valve 12', therefore, will remain closed and the shoe 3 can be drawn from the Wheel a distance proportional to the distance d corresponding to the prcdetern'iincd stroke accomplished by the piston 18 when the valve 12 Was opened.

The arrangement shown in Figure 2 obtains the same result by a. mechanical control.

For this purpose the counter-rod (38 of the piston 5 is provided at its end with a pivoted catcl'i 78 which is normally maintained in the position shown in the drawings by a spring (39.

When the handle 72 controlling the valve provided upon the duct 73 connecting the reservoir 9 with the space 25 in which the piston 5 moves is brought into its opening position, liquid under pressure Afrom the reservoir 9 acts on the piston 5 and displaces it to the right, thus rocking the bell-crank lever 76 by the action oi the catch 78 which hits one arm ot the`bell-crankg the other arm effecting the opening oi' valve 12 controlled by spring 77. The opening of this valve pern'iits the liquid under pressure to pass into the duet l1 and be delivered thereby into the cylinder 30 in which moves the piston 57 the rod ot' which is articulated on the lever 1. connected by link 33 to the brake niechanisni; the rod of the piston 5 i-s articulated on the lever 1 also connected by link 33 to the brake mechanism, the levers l and 1 being connected together by rod 79 and by a spring 80, so that the braking action will take place when the levers 1 and 1 are displaced in the directions oi' the arrows.

The length of the nose of the catch 7 8 and also the arm of the bell-crank 76 against which it acts will be such that when the piston 5 is being displaced to the right, the valve 12 remains open during a certain stroke during which the liquid under pressure may act on the piston 57 in order to press the shoes, not shown, against the wheel. The valve then continues to remain open and the piston 5 continues to move to the right, displacing the lever 1 connected to it and causing said lever to exert a traction action on spring 80. The said piston 5 having a much larger surface than piston 57, the effort which it receives is much greater than that received by piston 57, so that the latter will be moved to the right by the pull exerted on its lever 1 by spring 80, thereby forcing back the liquid through the valve 12 into the space 25 wherein piston 5 moves.

The valve 12 then closes and piston 5 continues its stroke to the right in order to exert the desired braking action.

When the releasing of the brakes is effected by an appropriate means not shown, the piston 5 moves back to the left and the catch 78 takes up again its position against the bell-crank lever 7G by passing under this so that at the moment of the releasing of the brakes the valve 12 will not be open. The piston 57 will remain in the position into which it was brought.

The space between the slices and the wheels necessary l'or complete release of the brakes will thus approximately correspond to the stroke cllected by the piston 5 when the applying movement takes plaee and during opening oi the valve 12'.

It goes without saying that the tension of the spring 77 must be higher than the maximum braking pressure existing in the space 25 in which moves the piston 5.

The construction shown in the Figure 3 likewise includes a lever l ior connection lo the brake mechanism, and a piston 57 guided in a cylinder 6. the other end ot which is closed by a dill'erential piston 18. 'lhe parl (L of this dill'erential piston has secured to it an axial rod 79 including a cam member 8() which at the beginning of the displacement ole the piston 1S raises the siem ot a springr valve 81 arranged in the duct 1l leading from the reservoir f) and connected by an extension 39 to the cylinder (i in which (he pistons move; duct 11 heilig also controlled hy an automatic valve 82. This arrangcment, which is based on the same principle as that shown in Figure l, will therefore pern'iit the liquid to be forced hack from the cylinder to the reservoir 9 and will also permit in any case a certain dislilaeement of the piston i8 producing no braking effort.

Then the cam S() has almost disengaged the rod o l the valve 8l, or has passed beyond it7 a second cam S3 on rod 7) will raise the rod of a spring-pressed valve 84 arranged in a. branch `ll of duct 1l, thereby short-cir cuiting the valves 8l and 82.

The operation is substantially as follows: When the differential piston 1.8 moves to the right, the cam 8O on its rod 7S) engages the .stem of rod 8l and opens it, whereupon the pressure liquid entersl the upper portion of duct 1l. but cannot pass theretrom to the. space or cylinder because valve 82 is closed. During the movement oi said piston, the pressure ol the liquid contained in space G increases and can become high enough to apply the brakes, at which point it almost balances the pressure in reservoir 9. But il' it tends to exceed that pressure. then the liquid in said space will be forced back into the reservoir through they automatic valve 82 and the then open valve 8l. At the moment when the cam 83 on rod 79 engages the rod of valve 84, the rod oi valve Si will leave -am 8() and said valve .Uil will close and valve S4: will open. It the pressure in space 6 stays less than that in reserllt] voir 9, then the liquid in said reservoir Will pass into said space and will act on piston 57 in such a way as to apply'the shoes against the wheels. Atter the rod oit valve 84 leaves cani S3, the braking proper takes place.-

In the construction shown, liquid under pressure for actuating the differential piston will be supplied behind its larger member o from the reervoir 9 by a duct 85 equipped with a suitable valve. The automatic valve 82 may, it desired, be replaced by a valve similar to valve Sil and having its stem or rod operable by cam 83, in which event valve 84 and duct 11 willbe omitted.

Figure l concerns a modification in which the duct 11 connecting the reservoir 9 and the braking cylinder in which moves the piston 57 is controlled conjointly by a. valve 12,"l operated by the core 89 oit a'sinall solenoid 63"* which controls 'the braking `torce, and by a second valve 12 interposed in the same conduit and which is controlled by the displacement of the member 18b of the difierential piston.

In the construction shown, the solenoid core also operates a valve 87 controlling` the braking torce. Besides, the releasing` o't the brakes is effected by the action ot a large solenoid 86 which brings back the dil'l'erential piston and it'orces back liquid under pressure into the reservoir 9 through the valve 8S.

The position ot' the parts shown in the ligure corresponds to the releasing of the brakes. In order to apply the brakes, current is shut oill from the small solenoid (33% The core member 89 is then displaced and also the valves 12n and 87 which are opened. Liquid under pressure acts on the piston 18 which is moved to the right and immediately rocks the bell-crank 76, thereby opening valve 12 against the action ot spring 77. The liquid under pre-:sure is then directly delivered by the duct 11 into the cylinder in which the piston 5T moves so that the brakes are immediately applied. The valve 12 remains open as long as its cam 78 is in con tact with the bell-crank 76. lVhen those parts are separated the real braking eliort begins. At the moment oit release which is etl'ected by energizing the solenoid 86 the valve 12Et is not opened tor the reason that the solenoid 63 is then also energized.

Vilhat I claim is: 1. A brake mechanism comprising a cylinder filled with liquid, a piston moving in said cylinder and' connected to the brakes; a brakes control device acting upon said liquid., means under tension for automatically applying the brakes, and means for controlling the entr1 into action of the first named means by the first movement of the brakes control device when displaced in lthe direction corresponding to braking, and for terminating such action after the completion stroke of the said control device in braking direction. Y

8. A brake mechanism comprising a cylinder lilled with liquid, a piston moving in said cylinder and connected to the brakes, a brakes control piston acting upon said liquid and actuated to apply and release the brakes, a chamber containing lliquid surmounted by a gas under pressure, a valve controlled communication between said chamber and said cylinder, means vfor opening the said communication by the lirst movement of said control piston, andmeans for closing the said communication after the completion of a predetermined stroke ol the control piston and Amaintaining it closed until the said control piston has been returned to releasing position and again displaced in braking direction.

4l. A brake mechanism comprising a cylinder filled with liquid, a piston moving in said cylinder and connected to the brakes, a brakes control piston acting upon said liquid, a chamber containing `liquid surmounted vby a gas under pressure, a valve controlled i communication between said chamber and said cylinder, mechanical means lor opening a valve disposed in said communication during the first part of the stroke olf said control piston, and means for maintaining said communication close-d during the releasing stroke. l y

5. A brake mechanism comprising a. cylinder lilledwith liquid, a piston moving in said cylinder and connected tothe brakes, a brakes-control piston acting upon said liquid, a chamber containing liquid surinounted by a gas under pressure, a valve controlled communication between said chamber and said means for opening a valve disposed in said communication during the first part of the stroke rof said control piston, a second valve disposed in said duct, and means for maintaining the second valve closed during the releasing stroke.

G. A brake mechanism comprising a cylinder lilled with liquid, a piston moving in said cylinder and connected to the brakes,

and for closing said communicalion utter the completion of a predetermined cylinder, mechanical` l (lll a second cylinder, connected with the first one, a brake control piston moving in the second cylinder, a chamber containing liquid sui-mounted by a gas under pressure, a communication between said chamber and said cylinders, a valve in said communication positively opened by the second named piston, a second valve disposed in said communication and opening towards said chamber, a third cylinder ot' greater section than the second one containing a third piston rigidly connected with the second one, and a valve controlled communication between said third cylinder and said chamber.

7. A brake mechanism comprising a cylinder iilled with liquid, a. piston moving in said cylinder and connected to the brakes, a second cylinder connected with the first one, a brake control piston moving in tlie second cylinder, a chamber containing liquid surmounted by a gas under pressure, a comprising a non-return valve opening towards said chamber and near said non-return valve a valve adapted to open under the gas pres`- sure but maintained on its scat by electrical means which also control the second valve disposed in the communication between the said chamber and the cylinder containing the piston connected to the brakes, and electrical means for displacing the third piston towards the releasing position.

ln testimony whereof ll aliix my signature.

HENRI PTEPER. 

